There shall be a provision that a grace period of 30 days or, at the option of the insurer, of 1 month of not less than 30 days, or of 4 weeks in the case of industrial life insurance policies the premiums for which are payable more frequently than monthly shall be allowed within which the payment of any premium after the first may be made, during which period of grace the policy shall continue in full force. The insurer may impose an interest charge not in excess of 6% per annum for the number of days of grace elapsing before the payment of the premium, and, whether or not such interest charge is imposed, if a claim arises under the policy during such period of grace, the amount of any premium due or overdue, together with interest and any deferred installment of the annual premium, may be deducted from the policy proceeds. Grace shall date from the premium due date specified in the policy.